Syringe.



PATENTED MAY 2, 1905.

G. A. HULETT.

SYRINGE.

APPLICATION 21mm OOT. 13,1903.

TVA 027 60? ap g4; 17. f/uie (it MQOW W W Minn STATES Patented May 2,1905.

GEORGE A. HULET'I, OF ANN ARBOR, MICHIGAN.

SYRINGE.

SPECIFICATION forming part of Letters Patent No. 789,092, dated May 2,1905.

Application filed October 13, 1903. Serial No. 176,919.

To It 1071,0711, it may concern:

Be it known that I, GEORGE A. I-IULETT, a citizen of the United States,residing at Ann Arbor, in the county of Washtenaw and State of Michigan,have invented certain new and useful Improvements in Syringes,of whichthe following is a specification, reference being had therein to theaccompanying drawings.

The invention relates to improvements in syringes; and it is the specialobject of the invention to obtain a simple and inexpensive constructionwhich is particularly adapted for hypodermic injections.

The invention consists in the peculiar construction, arrangement, andcombination of parts, as hereinafter set forth.

In the drawings, Figure 1 is a longitudinal section through theinstrument. Fig. 2 is a section showing the tube or cylinder in dottedlines. Fig. 3 is an elevation of the device complete.

A is a cylinder or tube, preferably formed of glass, having one endcontracted to form the nipple B. In this nipple the needle 0 may besecured by suitable cement D. Placed within the cylinder is the plungerE, which may be formed of wood or any other suitable material and is ofa diameter slightly less than that of the tube.

F is the plunger-head or piston. This is formed of a compressibleresilient substance and is of a conical form, the outer end being of adiameter which is slightly in excess of the diameter of the tube, sothat it will be slightly compressed at its outer end when inserted intothe cylinder. The inner end is secured to the plunger E, preferably byforming a recess in the end of the latter and cementing or otherwisesecuring the parts together, so as to get a solid connection between thesmaller end of the piston and its plunger.

The cylinder A is preferably formed at its outer end with a flaringflange G. This permits of inserting the plunger, as the large endthereof may be forced in the flaring end of the tube and in movinginward will be compressed until it snugly fits the tube or cylinder.

In operation the liquid may be placed in the tube A, after which theplunger is inserted in the manner just described. On account of thecompressible and resilient character of the plunger-head or piston F itwill form an absolutely liquid-tight joint with the walls of the tube,and by being compressed between the material in front of the piston andthe solid backing afforded by the plunger the length of the jointbetween the piston and its cylinder will be increased just in proportionto the force behind and the resistance of the material in front. Thus Iobtain a packing for the piston which is always tight and automaticallytightens in proportion to the pressure required to force the liquid out.

hat I claim as my invention is 1. The combination with a cylinder of aplunger therefor comprising a shank having a converging head formed ofresilient compressible material, secured at its smaller end to the innerend of said shank, the maximum diameter of said head being atits extremeouter end greater than the diameter of the cylinder and being adapted tobe compressed to fit within said cylinder, substantially as and for thepurpose described.

2. The combination of a cylinder, of a plunger therefor a piston ofresilient material of the form of a solid truncated cone having itssmaller end secured to the inner end of the plunger, and its larger endextending beyond the sides of the plunger and fitting the cylinder,whereby when pressure is applied to the plunger, the joint formedbetween the piston and cylinder will-be tightened proportionate to thepressure on the plunger, and the resistance of the liquid.

3. The combination with a cylinder of a plunger therefor comprising ashank having an inner terminal recess and a head of compressiblematerial, secured within the recess and extending at its outer endbeyond the sides of the rod.

4:. A hypodermic syringe comprising a tube partially closed at one endto form a nipple of tapering shape upon its interior, a needle withinsaid nipple, and cement surrounding said needle Within the taperedportion of the nip- In testimony WhereofIatfix my signature in ple, tosecure the same to said tube. presence of two Witnesses.

5. The combination with a cylinder of a GEORGE A HULETT 4 plungertherefor comprising" a shank having a 5 tapered terminal recess, and aconical head of Witnesses:

resilient material fitted Within said recessed A. J. SAWYER, portion ofthe plunger. A. J. SAWYER, Jr.-

